Low-emission dispersion paints, coating materials and synthetic resin dispersion plasters as well as processes for the preparation thereof

ABSTRACT

Production of low-emission dispersion paints, coating materials and synthetic resin dispersion plasters in the form of aqueous preparations based on aqueous synthetic resin dispersion copolymers derived from olefinically unsaturated monomers, having a pigment volume concentration (PVC) of at least 60% and containing water, fillers, pigments, synthetic resin dispersion copolymers and conventional auxiliaries, wherein the synthetic resin dispersion copolymers have a content of 0.05 to 2% by weight of monomer units derived from special unsaturated hydrolyzable organic silicon compounds and the aqueous copolymer dispersions possess a minimum film-forming temperature (MFT) of &lt;10° C., preferably &lt;5° C. and especially &lt;2° C., the aqueous preparations according to the invention contain &lt;0.1% by weight of volatile non-aqueous constituents, based on the total non-volatile part of the preparations, and the pH of the aqueous preparations is in the range from 5.5 to 10.

PRIOR APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.855,734 filed Mar. 19, 1992 which is a continuation of U.S. patentapplication Ser. No. 633,276 filed Dec. 24, 1990 which is a continuationof U.S. patent application Ser. No. 306,881 filed Feb. 3, 1989, all nowabandoned.

The invention relates to low-emission dispersion paints, coatingmaterials and synthetic resin dispersion plasters in the form of aqueouspreparations based on aqueous synthetic resin dispersions having apigment volume concentration (PVC) of at least 60% which are free fromorganic solvents and volatile organic film-forming auxiliaries andlow-molecular weight plasticizers, and which are free from readilyvolatile non-aqueous constituents and from malodorous by-products,furthermore to processes for the preparation thereof and to the usethereof as construction protective materials and as structuralmaterials, especially in spaces that are inadequately ventilated and areinhabitated.

In order to reduce pollution by noxious substances it is often desirablefor aqueous dispersion paints, coating materials and synthetic resindispersion plasters, when used in the open or especially in enclosedspaces, to be unable to liberate, apart from water, any non-aqueousvolatile organic or inorganic constituents.

However, according to the state of the art, construction protectivematerials such as, for example dispersion paints, plasters, mastics, andliquid adhesives, contain more or less large amounts of solvents. Thereadily volatile or the moderately to slightly volatile additives hereused as solvents or film-consolidating or film-forming auxiliaries oralso as plasticizers, are generally indispensable for achieving therequired application properties of the construction protectivematerials. In order to attain high wet abrasion resistance, mechanicalstrength, low tendency to soiling and to blocking of the used materials,it has not been hitherto possible to employ dispersion polymers whoseaqueous dispersions possess a freezing or glass temperature (Tg) or aminimum film-forming temperature (MFT) in the neighborhood of 0° C.These application properties could accordingly only be achieved by theuse of polymer dispersions having a Tg or MFT distinctly above 0° C. inconjunction with film-forming auxiliaries which reduce the Tg or MFT,with the result that it was possible to employ them even at, or, ifdesired, below 5° C. Film-forming auxiliaries andtemporary-plasticizers, however, migrate into the atmosphere on drying,which may be toxicologically hazardous especially with indoor paints,for example through unpleasant odor or through inhalation by sensitivepersons.

Permanent plasticizers have also been used in the past. This can lead toshortcomings due to increased tackiness, plasticizer migration as wellas to possible volatility.

Experiments were also undertaken into using vinyl acetate dispersioncopolymers, especially vinyl acetate/ethylene copolymer dispersionswhich possess a Tg or a MFT in the neighborhood of 0° C.

It was found, however, that the pigment binding power of suchdispersions is limited compared with systems having binders obtainedfrom harder dispersion copolymers with additions of film-consolidatingauxiliaries.

Thus the object forming the basis of the present invention has been tomake available such aqueous dispersion paints, coating materials andplasters which contain no significant proportions of non-aqueousvolatile compounds apart from water and which contain as binderssynthetic resin dispersions which are free from film-formingauxiliaries, and which have a high pigment binding power per se andmoreover whose films possess low tendency to soiling and to blockingeven at a low Tg or low MFT of the dispersion.

It has now been found, surprisingly, that the foregoing difficulties maybe overcome by using dispersions of such synthetic resin dispersioncopolymers whose copolymer macromolecules contain small amounts ofmonomeric units derived from unsaturated hydrolyzable organic siliconcompounds and possess the required Tg and MFT values, and furthermorethe dispersions are virtually free from volatile non-aqueous organicand/or inorganic constituents.

Accordingly, the subject matter of the invention are low-emissiondispersion paints, coating materials and synthetic resin dispersionplasters in the form of aqueous preparations based on aqueous syntheticresin dispersion polymers derived from olefinically unsaturated monomershaving a pigment volume concentration (PVC) of at least 60% andcontaining water, fillers, pigments, synthetic resin dispersion polymersand auxiliaries selected from the group wetting agents, dispersants,emulsifiers, protective colloids, thickeners, antifoams, dyes andpreservatives, wherein the non-volatile part of the aqueous preparationscontains

35 to 94% by weight of a filler,

2 to 30% by Weight of a pigment,

0.1 to 10% by weight of an auxiliary and

4 to 35% by weight of a synthetic resin dispersion copolymer, based onthe total non-volatile part, the aqueous dispersion of which copolymerpossesses a minimum film-forming temperature (MFT) of <10° C.,preferably <5° C., particularly <2° C., and the synthetic resindispersion copolymer has a content of 0.05 to 2% by weight, preferably0.1 to 0.4% by weight, particularly 0.05 to 0.2% by weight, based on thesynthetic resin dispersion copolymer, of monomeric units derived fromunsaturated hydrolyzable organic silicon compounds of the formula I,##STR1## in which R denotes an organic radical olefinically unsaturatedin the ω-position and R¹ R² and R³ which may be identical or different,denote halogen, preferably chlorine, or the group -OZ, Z denotingprimary or secondary alkyl or acyl radicals optionally substituted byalkoxy groups, or hydrogen, the content of volatile non-aqueousconstituents of the aqueous preparations being <0.1% by weight,preferably <0.05% by weight, based on the total non-volatile part, andthe pH of the aqueous preparations being in the range from 5.5 to 10,preferably 7 to 9, particularly 8 to 9.

A preferred embodiment of the invention comprises the synthetic resindispersion copolymer used containing monomeric units selected from thegroup vinyl esters, vinyl esters/ethylene, vinyl esters/vinylchloride/ethylene, vinyl esters/vinyl versatates, vinyl esters/acrylicesters and acrylic esters/vinyl versatates/ethylene, in addition tomonomeric units derived from compounds of the formula I.

Preferred compounds of the formula I are, for example,γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane,vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethylglycolsilane, vinyltriacetoxysilane, vinyltrichlorosilane,vinylmethyldichlorosilane andγ-methacryloxypropyltris(2-methoxyethoxy)silane.

A particular variant of the invention is for the synthetic resindispersion copolymer used to comprise mixtures of dispersion copolymers,a part of which contains no monomeric units of the formula I and anotherpart of which contains monomeric units of the formula I in such anamount that the mean content of monomeric units of the formula I in thetotal dispersion copolymer mixture is 0.05 to 2% by weight, preferably0.1 to 0.4% by weight, particularly 0.05 to 0.2% by weight, based on thetotal synthetic resin dispersion copolymer mixture.

Furthermore, a particular feature according to the invention is that theaqueous preparations according to the invention are free from readilyvolatile residual monomers, from low alcohols and from ammonia and/orvolatile amines or from components which give rise by cleavage to H₂ Sor mercaptans, if appropriate, and the total content of volatilenon-aqueous constituents of the aqueous preparations is <0.05% byweight, based on the total non-volatile part.

The preparation of synthetic resin copolymer dispersions, where themonomers are copolymerized with hydrolyzable, unsaturated organicsilicon compounds of the formula I, is known.

Synthetic resin dispersions based on vinyl acetate with 0.5. to .1% byweight, based on the total amount of monomers, of a copolymerizablesilane, such as, for example, vinyltrimethoxysilane,γ-methacryloxypropyltrimethoxysilane and vinyltris(2-methoxyethoxy)silane, are known from U.S. Pat. No. 3,729,438. Thepolymer crosslinks on drying, giving rise to a clear, high-gloss film.

U.S. Pat. No. 3,814,716 describes synthetic resin dispersions based onvinyl acetate, acrylic esters, maleic and fumaric esters with 0.5 to 5%by weight of a copolymerizable silane. On drying the synthetic resindispersion yields clear, high-gloss and crosslinked films with excellentwater and solvent resistance.

The use of polymeric binders in aqueous dispersion for the preparationof structural coating materials are known from DE-PS 2,148,457, wherethe synthetic resin dispersions contain polymers from vinyl esters,acrylic esters or butadienestyrene copolymers into which the silanolgroups have been introduced by polymerization.

The preparation of aqueous synthetic resin dispersions based on vinylesters of carboxylic acids of 2 to 18 carbon atoms, ethylene, optionallyup to 25% by weight of other olefinically unsaturated monomers and 0.3to 5% by weight, based on the total amount of monomers, of anunsaturated hydrolyzable organic silicon compound, is known from DE-PS2,148,458. Films prepared from the synthetic resin dispersions describedexhibit with copolymers containing 1 to 2% by weight of the siliconcompounds named above, high drying and wet peeling strengths on glassand asbestos cement. However, the synthetic resin dispersion preparedaccording to Example 1 of the above DE-PS possesses a 0.2% by weightcontent of unreacted monomeric vinyl acetate and the synthetic resindispersions prepared according to Examples 6 and 10 contain,respectively, 3.8 and 4.8% by weight of methanol, in each case based onthe polymeric part.

It cannot be simply assumed or deduced from the above state of the artthat synthetic resin dispersions containing silanol groups may also giverise, in addition to a high pigment binding power in dispersion paints,to an improvement of the pull-off resistance of the coatings produced bythe paints and, in addition, to a low tendency to soiling and blockingof the films or coatings produced therefrom, despite a low Tg and a lowMFT.

It was therefore the more surprising to find that with binders based onsynthetic resin dispersions having a low MFT, in the absence of volatileorganic film-forming auxiliaries, a marked improvement of the binderproperties is achieved if the dispersion copolymers contain only verysmall amounts of monomeric units with silanol groups formed fromcompounds of the formula I, amounts from 0.1 to 0.4% by weight, based onthe total amount of monomer, being preferred.

A preferred embodiment of the present invention further is that thesynthetic resin dispersion copolymer contained in the aqueouspreparations and carrying silicon radicals in the monomeric units of theformula I was prepared by radically initiated copolymerization of thefinely divided monomers having an amount of 0.05 to 2% by weight,preferably 0.1 to 0.4% by weight, particularly 0.05 to 0.2% by weight,based on the total amount of monomer, of monomers of the formula I inaqueous medium with the simultaneous use of hydroxyethylcellulose,non-ionic emulsifiers and monomeric sodium vinylsulfonate asemulsifier/protective colloid system, and the volatile alcoholcomponents which may have formed by hydrolysis from the monomeric unitsof the formula I in the aqueous dispersion and any volatile amounts ofresidual monomers which may be present after the terminatedpolymerization reaction have been removed by physical methods,preferably by distillation under reduced pressure.

In the preparation of the synthetic resin dispersion copolymers, forexample by emulsion polymerization, the alkoxy, acyloxy and halogenradicals of the silicon compounds of the formula I used hydrolyze atleast partially to give silicon compounds containing hydroxyl groups(silanol groups) which are then contained in the copolymer and may leadto crosslinking between the macromolecules.

Suitable hydrolyzable unsaturated organic silicon compounds of theformula I are preferably those in which the radical R in the formula Irepresents an ω-unsaturated alkenyl of 2 to 10 carbon atoms,particularly of 2 to 4 carbon atoms, or an ω-unsaturated carboxylic acidester formed from unsaturated carboxylic acids of up to 4 carbon atomsand alcohols carrying the Si group of up to 6 carbon atoms. Suitableradicals R¹, R², R³ are preferably halogen, particularly chlorine, andthe group -OZ, Z representing primary and/or secondary alkyl radicals ofup to 10 carbon atoms, preferably up to 4 carbon atoms, or alkylradicals substituted by alkoxy groups, preferably of up to 3 carbonatoms, or acyl radicals of up to 6 carbon atoms, preferably of up to 3carbon atoms, or hydrogen.

Examples of such compounds of the formula I are vinyltrichlorosilane,vinylmethyldichlorosilane,γ-methacryloxypropyltris(2-methoxyethoxy)silane, vinylmethoxysilane,vinyltriethoxysilane, vinyldiethoxysilanol, vinylethoxysilanediol,allyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane,vinyltributoxysilane, vinyltriacetoxysilane, trimethylglycolvinylsilane,γ-methacryloxypropyltrimethylglycolsilane,γ-acryloxypropyltriethoxysilane andγ-methacryloxypropyltrimethoxysilane.

The removal of residual monomers in the synthetic resin copolymerdispersions used according to the invention may also be carried out byresorting to known chemical methods such as, for example, by radicallyinitiated, preferably using redox catalysts, secondary polymerization.Should subsequently traces of volatile monomers be still present in thedispersion, these can be readily removed by other methods, preferably byphysical methods, particularly by distillation, preferably under reducedpressure and, if desired, by passing inert carrier gases such as, forexample, air, nitrogen, CO₂ or steam, through or over the reactionmixture.

A particular feature of the present invention is also the fact that thesynthetic resin copolymer dispersions used according to the inventionare not only free from volatile residual monomers, but also that anyvolatile alcohols forming or formed in the hydrolysis of the usedcomonomers of the formula I, such as, for example, methanol,methoxyethanol or isopropanol, have been removed by the aftertreatmentreferred to above using chemical and/or physical methods. This may be ofconsiderable significance when, for example, vinyltrimethoxysilane isused as comonomer, since the methanol formed by hydrolysis and presentin the resultant dispersion may prevent the use of the dispersion ontoxicological grounds, if the methanol has not been eliminatedbeforehand.

The aqueous preparations according to the invention comprise in theirfinal composition to be used as construction protective materials orstructural materials, if appropriate, preferably also the followingcomponents as further auxiliaries in addition to the constituents fromthe synthetic resin copolymer dispersion:

0.1 to 0.6% by weight of a wetting agent or dispersant for filler andpigment,

0.1 to 1% by weight of a thickener,

0.01 to 2% by weight of a preservative and

0.001 to 0.5% by weight of an anti-foam,

each based on the total weight of the aqueous preparations.

The aqueous preparations according to the invention in the form ofdispersion paints, coating materials and synthetic resin dispersionplasters, using synthetic resin dispersion copolymer latices accordingto the invention, which preparations are free from residual monomers andother volatile constituents, may be prepared by application of knowntechniques, such as they are used in the preparation of conventionalproducts of this type using conventional synthetic polymer latices.However, it is important that in the choice of the usual startingmaterials attention is paid particularly to their freedom from ammonia,amines, ammonium compounds, alkyl ammonium compounds, solvents, H₂ S,SO₂ and formaldehyde as well as freedom from other volatile organicsubstances.

Preferred fillers used are, for example, calcium carbonate, magnesite,dolomite, kaolin, mica, talc, silica, calcium sulfate, feldspar, bariumsulfate and plastic beads.

Examples of white pigments used are zinc oxide, zinc sulfide, basic leadcarbonate, antimony trioxide, lithopone (zinc sulfide+barium sulfate)and, preferably, titanium dioxide.

Examples of inorganic colored pigments which may preferably be used areiron oxides, carbon black, graphite, luminescent pigments, zinc yellow,zinc green, Paris blue, ultramarine, manganese black, antimony black,manganese violet or Schweinfurt green.

Suitable organic colored pigments preferably are, for example, sepia,gamboge, Cassel brown, toluidine red, para red, Hansa yellow, indigo,azo dyes, anthraquinone and indigo dyes as well as dioxazine,quinacridone, phthalocyanin, isoindolinone and metal complex pigments ofthe azomethine series.

The fillers may be used as individual components. Mixtures of fillerssuch as, for example, calcium carbonate/kaolin and calciumcarbonate/kaolin/talc have been found to be particularly useful inpractice. To increase the hiding power and to save on titanium dioxide,finely divided fillers such as, for example, finely divided calciumcarbonate and mixtures of various calcium carbonates with differentparticle size distribution are frequently used.

To adjust the hiding power, the shade and the depth of color the fillersare mixed with appropriate amounts of white pigment and inorganic and/ororganic colored pigments.

To disperse the fillers and pigments in water, 0.1 to 0.6% by weight,based on the total weight of the aqueous preparation, of auxiliariesbased on anionic or non-ionic wetting agents, such as preferably, forexample, sodium pyrophosphate, sodium polyphosphate,naphthalenesulfonate, sodium polyacrylate, sodium polymaleinates andpolyphosphonates such as sodium 1-hydroxyethane-1,1-diphosphonate andsodium nitrilotris(methylenephosphonate), may be added.

Thickeners which may be used, are inter alia preferably cellulosederivates such as methylcellulose, hydroxyethylcellulose andcarboxymethylcellulose. Other thickeners which may be used, are casein,gum arabic, gum tragacanth, starch, sodium alginate, polyvinyl alcohol,polyvinylpyrrolidone, sodium polyacrylate and water-soluble copolymersbased on acrylic and methacrylic acid, such as acrylic acid/acrylamideand methacrylic acid/acrylic ester copolymers.

Inorganic thickeners, such as, for example, bentonites or hectorite, mayalso be used.

Such thickeners are generally employed in amounts from 0.1 to 3% byweight, preferably 0.1 to 1% by weight, based on the total weight of theaqueous preparations.

The thickener may be incorporated already during the dispersion of thefillers and pigments in water with the addition of a dispersant and, ifdesired, an antifoam, for example using a dissolver; however, thethickener may also be added to the finished preparation, provided thatthe water balance of the finished construction protective materialpermits this to be done.

The synthetic resin copolymer dispersion used as binder according to theinvention may already be present during the dispersion of the pigmentand filler, but in most cases it is advantageously added to thefiller/pigment paste which is still hot or also cooled, under rapid oralso slower stirring. In order to maintain a pigment volumeconcentration of >60%, 4 to 35 parts by weight of synthetic resindispersion copolymer are used per 65 to 95.9 parts by weight offiller+pigment.

The preparation of the copolymer dispersions for the aqueousconstruction protective material preparations low in noxious substancesemission according to the invention is carried out in known manner,preferably by emulsion polymerization in the presence of a radicallyinitiated catalyst and at least one emulsifier at a pH of 2 to 6. Thevarious known catalysts forming free radicals or also redox systems maybe used as catalysts. The concentration range of the total amount ofemulsifiers is preferably between 0.5 and 5% by weight, based on thetotal amount of monomer, where the emulsifiers may be anionic, non-ionicor, if appropriate, cationic emulsifiers. It is also possible to uselatex stabilizers, such as, for example, water-soluble polymers selectedfrom the group carboxymethylcellulose, hydroxyethylcellulose,polyvinylpyrrolidone, poly-N-vinylacetamide, polyvinyl alcohol as wellas combinations of emulsifiers and latex stabilizers, and also the knownstabilizing comonomers based on monocarboxylic and dicarboxylic acidsand the half-esters and amides thereof as well as vinylsulfonic acid andits salts.

Examples of monomers which are suitable for the preparation of thesynthetic resin dispersion, are vinyl esters, in particular vinyl estersof aliphatic monocarboxylic acids of 1 to 12 carbon atoms, for examplevinyl esters of lower (C₁ -C₆)carboxylic acids such as vinyl acetate,vinyl propionate, vinyl butyrate, vinyl caproate, furthermore vinyllaurate, vinyl decanate and vinyl versatate, furthermore, for example,olefinically unsaturated compounds of the formula II, ##STR2## in whichR¹ denotes hydrogen, an alkyl radical of 1 to 4 carbon atoms, an alkoxyradical of 1 to 4 carbon atoms, a nitrile group, a halogen atom,preferably chlorine, or an alkoxycarbonyl radical of 2 to 12, preferably2 to 9, carbon atoms, and R² represents hydrogen, a methyl or a vinylgroup.

Examples of suitable monomers of the formula II are in particularolefins, for example ethylene and isobutylene, vinyl ethers, for examplevinyl methyl ether, vinyl ethyl ether and vinyl n-butyl ether,furthermore acrylonitrile, methacrylonitrile, vinyl chloride, acrylicacid esters of monohydric alcohols, for example methyl acrylate, ethylacrylate, butyl acrylate and 2-ethylhexyl acrylate, as well asmethacrylic acid esters of monohydric alkanols, for example methylmethacrylate, ethyl methacrylate, butyl methacrylate and 2-ethylhexylmethacrylate. Equally suitable are maleic acid diesters, in particularof monohydric aliphatic alcohols of 2 to 10, preferably 3 to 8 carbonatoms, for example dibutyl maleate, dihexyl maleate and dioctyl maleate.

The monomers or monomer mixtures are chosen in such a manner thathomopolymer-based, copolymer-based or terpolymer-based synthetic resindispersions having an MFT of ≦10° C., preferably ≦5° C., particularly≦0° C., are produced. Any person skilled in the art knows on the basisof the Tg of the polymers and the polymerization parameters whichmonomers or mixtures of monomers must be employed for this purpose.Since the MFT below 0° C. can no longer be measured, the lower limit ofthe MFT can only be specified by the Tg. In this connection the Tgshould not be below -20° C. preferably below -10° C. Suitable copolymersare, for example, vinyl acetate/ethylene in the ratio 86/14 to 75/25,such as may be prepared at an ethylene pressure in the region from 25 to60 bar. Other suitable copolymers are vinyl acetate/vinylchloride/ethylene terpolymers in the ratio 58.8/25.2/16, prepared at anethylene pressure of 40 bar and having an MFT of 10° C., or 60.8/15.2/24and 45 6/30 4/24, such as may be obtained at an ethylene pressure of 50bar and having an MFT of <0° C. and a Tg of -0.5 and +5.5° C.respectively. With vinyl acetate/butyl acrylate copolymer dispersionsthe suitable MFT range is obtained when the monomers are used in theratio 80/20 to 50/50.

The main monomers are copolymerized with small amounts, particularlypreferably with 0.05 to 0.3% by weight, based on the total amount ofmonomer, of olefinically unsaturated silicon compounds of the formula Icontaining hydrolyzable groups, the radical R in the formula Ipreferably denoting vinyl, allyl, γ-acryloxypropyl andγ-methacryloxypropyl, and R¹, R², R³ preferably denoting alkoxy of 1 to8 carbon atoms or alkoxyalkoxy of 2 to 10 carbon atoms, acetoxy orhalogen, in particular chlorine.

Examples of particularly preferred compounds of the formula I arevinyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethylglycolsilane,vinyltriacetoxysilane, γ-acryloxypropyltrimethoxysilane,γ-methacryloxypropyltrimethoxysilane,γ-methacryloxypropyltris-(2-methoxyethoxy)silane, vinyltrichlorosilane,vinylmethyldichlorosilane and allyltrimethoxysilane.

The silanes of the formula I may be added in the emulsioncopolymerization either mixed with the main monomers or separately. Theymay be metered in uniformly with the other monomers in the course of thepolymerization or either in the first or the second half of the monomeramount. Only relatively small amounts of the above silanes are requiredto improve the properties of the synthetic resin dispersion according tothe invention, preferably up to a maximum of 2% by weight, based on thetotal amount of monomers, preferably 0.1 to 0.4% by weight, particularly0.05 to 0.2% by weight.

Removal of the unreacted monomers from the synthetic resin dispersionmay be carried out chemically, i.e. for example by polymerization tocompletion. For this purpose catalysts forming free radicals areemployed. Examples of such catalysts are peroxide and azo compounds,such as, for example, azobis(isobutyramidine hydrochloride). Equallyparticularly suitable are the combination types of catalysts in whichboth reducing agents and oxidation agents are used. When combinationcatalysts of this type are used, the reducing agent is generally termedactivator and the oxidation agent initiator. Examples of suitableactivators are bisulfites, sulfoxylates or compounds having reducingproperties, such as, for example, ascorbic acid and ferrous salts.Examples of initiators are inter alia, hydrogen peroxide, persulfatessuch as sodium and potassium persulfate, perborates and also other perscompounds. Examples of special combination catalysts or redox systemswhich may be employed for the removal of the residual monomers bypolymerization, are inter alia hydrogen peroxide and zinc formaldehydesulfoxylate, hydrogen peroxide and sodium metabisulfite, sodiumpersulfate and sodium metabisulfite, hydrogen peroxide and sodiumsulfite, hydrogen peroxide and rongalite, sodium or potassium persulfateand sodium sulfite, sodium or potassium persulfate and rongalite,hydrogen peroxide and ascorbic- acid, tert-butylhydroperoxide and sodiumsulfite, tert-butylhydroperoxide and rongalite, sodium persulfate andsodium thiosulfate. Metal salts, used in traces, such as, for example, 1to 100 ppm per monomer equivalent of iron or copper salts, such as, forexample, Mohr's salt, may further activate the redox system. Examplesare tert-butylhydroperoxide/Mohr's salt/rongalite or sodiumpersulfate/sodium sulfite/sodium thiosulfate/copper sulfate.

The redox catalyst is typically used in an amount between about 0.1 andabout 2% by weight, preferably between about 0.25 and about 0.75% byweight, based on the amount of monomers. The activator is normally addedin aqueous solution and the amount of activator generally is 0.25 to 1times of the amount of initiator.

Physical methods, such as, for example, distillation, may also be usedfor the removal of residual monomers from the synthetic resindispersion. Furthermore it is possible to combine chemical and physicalmethods. The removal of the residual monomers by distillation may takeplace under elevated, but preferably also under reduced pressure. In theremoval of the residual monomers by distillation at 760 Torr or a lowerpressure, the demonomerization may be speeded up by passing steam or acarrier gas, such as, for example, air, nitrogen or carbon dioxide,across the surface of the synthetic resin dispersion. However, thecarrier gas is preferably passed in the demonomerization apparatus fromthe bottom through the synthetic resin dispersion. The residual monomersremoved by physical methods from the synthetic resin dispersion arerecovered by being condensed in a condenser. If a carrier gas is used inthe demonomerization, coolants having a lower temperature than waterfrom 0° to 30° C., for example cooling brine or acetone/dry ice, areemployed if appropriate in the condenser. Furthermore, the residualmonomers may be removed in vacuo and recovered from the synthetic resindispersion by the use of pumps with rotary slide valves. The content ofresidual monomers and other volatile organic substances possiblyoriginating from the starting materials or of volatile organicconstituents formed in the polymerization, and of the alcohol which isformed in the hydrolysis of the copolymerized silicon compound of theformula I in the synthetic resin copolymer dispersion to be usedaccording to the invention is less than 0.1% by weight, preferably 0.05to 0.001% by weight, based on the dispersion copolymer.

Surprisingly in the case of binders having a low MFT, thecopolymerization with tracers of copolymerizable silanes of the formulaI gives rise to dispersion copolymers of a pigment binding power asgreat as that normally only achievable with dispersion (co)polymershaving a high MFT, such as, for example, styrene/acrylate, when largeamounts of solvent are added to the synthetic resin dispersion or to adispersion paint prepared from it.

Synthetic resin copolymer dispersions based on vinyl acetate/ethyleneand vinyl acetate/vinyl chloride/ethylene are preferably used for theodourless aqueous preparations, low in noxious substances emission, ofconstruction protective materials, in addition to water, filler,pigment, dispersant, thickener, antifoam and preservative. To attain alow MFT, the ethylene pressure chosen must be higher in the case ofvinyl acetate/vinyl chloride/ethylene than in the case of vinylacetate/ethylene because of the higher freezing temperature of polyvinylchloride. The resultant dispersion copolymers or the aqueous dispersionsthereof have the advantage that copolymer dispersions may be madeavailable which possess the low MFT required according to the invention.

Furthermore, because of the low boiling points of the monomers used, thesynthetic resin dispersions prepared in this manner possess greatadvantages over styrene/acrylate and styrene/butadiene copolymers withtheir unpleasant by-products which may form, for example, by aDiels-Alder reaction.

The vinyl acetate/ethylene dispersion copolymers and the correspondingterpolymers with vinyl chloride may be advantageously prepared bycopolymerization in water with the aid of anionic, non-ionic or cationicemulsifiers in the form of aqueous dispersions. Water-soluble,stabilizing polymers such as carboxymethylcellulose,hydroxyethylcellulose, polyvinylpyrrolidone, poly-N-vinylmethylacetamideand polyvinyl alcohol can be used for this purpose, as well as the knownstabilizing comonomers based on monocarboxylic and dicarboxylic acidsand their half-esters and amides. Furthermore, known initiator systemssuch as, for example persulfates, sodium persulfate/sulfite andtert-butylhydroperoxide/Fe²⁺ /rongalite may be advantageously used forthe polymerization.

If the appropriate autoclaves are not available, such as are normallyrequired for the copolymerization with ethylene and/or vinyl chloride,it is also possible to obtain dispersion copolymers according to theinvention having the required MFT by copolymerization of customarymonomers with those monomers that can strongly lower the MFT, such as,for example, 2-ethylhexyl acrylate, dioctyl maleate, vinyl versatate orbutadiene. However, the copolymers and terpolymers based on vinylacetate/ethylene and vinyl acetate/vinyl chloride/ethylene possess thequite considerable advantage that because of their low boiling pointstheir starting monomers are readily freed from the residual monomer partwhich has not reacted in the polymerization.

By choosing appropriate technical measures, it is furthermore possibleto use the recovered residual monomers for further polymerizations.

The above dispersion copolymers based on vinyl acetate/ethylene andvinyl acetate/vinyl chloride/ethylene with comonomers of the formula Iare particularly preferred according to the invention.

By the combination of redox and strip processes or by the strip processalone for removing the residual monomers, the proposition is made herefor the first time in connection with the preparation of low-emissionconstruction protective materials according to the invention and the useof hydrolyzable and copolymerizable silanes of the formula I for theremoval of mostly readily volatile alcohols formed in the hydrolysis ofsilanes. A special and preferred embodiment of the invention ofunexpectedly great technical advance is based on the following mode ofoperation. Synthetic resin copolymer dispersions are prepared whichcontain, for example hydroxyethylcellulose orpoly-N-vinylmethylacetamide as protective colloids and which contain inaddition to these protective colloids preferably non-ionic emulsifiersand in addition to non-ionic emulsifiers only small amounts of ionicsuch as anionic or cationic emulsifiers. It is advantageous in thisconnection for further stabilization of the copolymer dispersion to useat the same time unsaturated hydrophilic comonomers capable ofcopolymerization, such as, for example, unsaturated monocarboxylic anddicarboxylic acids and their half-esters and amides as well as sodiummethacrylamido-2-methyl-2-propanesulfonate or sodium vinylsulfonate.Synthetic resin copolymer dispersions are thus obtained with not verysmall particle sizes, such as, for example, ≦0.1 μm, but with meanparticle sizes of at least 0.1 μm, preferably ≧0.15 μm, particularly≧0.2 μm. They are distinguished by outstanding application properties,such as, for example, in that the synthetic resin dispersions arereadily miscible with dry fillers and pigments and the constructionprotective materials prepared therefrom are highly resistant over theusual extended storage period.

For many years vain attempts were made by experts to prepare thesedispersions, as advantageous on account of their application propertiesas those based on vinyl acetate/ethylene and vinyl acetate/vinylchloride/ethylene and also possessing very high pigment binding power.This object has now been achieved in an unexpectedly advantageous mannerby the present invention by the use of dispersion copolymers whichcontain comonomeric units derived from silicon compounds of the formulaI, which units carry small amounts of hydrolyzable silicon-containingradicals or which form Si(OH)_(x) groups (x=1 to 3), and whose aqueousdispersions have an MFT of <10° C. When these dispersion copolymers areused as binders in the aqueous preparations of construction protectivematerials under discussion, the so-called crazing of the dried coatingand of the dried coating even after only a brief drying period of thepreparation, as assessed by the resistance to washing and shearing ofcoatings according to DIN 53,778, surprisingly does not occur, despitethe absence of solvents and film-consolidating auxiliaries, i.e thecoating does not possess inadequate mechanical strength after a briefdrying period, as can be frequently observed with paints derived frompolymer dispersions.

Those aqueous preparations of construction protective materialsaccording to the invention are particularly suitable and preferred whichcontain solvent-free synthetic resin copolymer dispersions having a lowMFT as binders and whose copolymers contain in toto only small amountsof monomeric units derived from silicon compounds of the formula I,which units are capable of copolymerization and carry hydrolyzablesilicon-containing radicals or form Si(OH)_(x) groups (x=1 to 3), viz.preferably 0.05 to 2% by weight, particularly 0.1 to 0.4, particularlypreferably 0.05 to 0.2% by weight, based on the copolymer, and thecopolymers were prepared by emulsion copolymerization from combinationsof comonomers which result in the required low MFT values, in thepresence of hydroxyethylcellulose, a non-ionic emulsifier, small amountsof monomeric vinyl sulfonate, with the addition in toto of only smallamounts of comonomers of the formula I.

In order to tint dispersion paints and dispersion plasters, commerciallyavailable pigment pastes are frequently used. These pigment pastesgenerally contain solvents for reasons of stability or theirpreparability. A novel path has also been taken according to theinvention for overcoming the resultant difficulties. Because of the highstability of the synthetic resin copolymer dispersion used according tothe invention and its compatability with dry pigments, the preparationand use of pigment pastes containing solvents is unnecessary, since thepigment may be admixed with the synthetic resin dispersion or the whitedispersion paint or the dispersion plaster in the dry state, if desired.

The advance in properties achievable in dispersion copolymers having MFTvalues of their aqueous dispersions of <10° C. in the case of theaqueous preparations of construction protective materials according tothe invention prepared therefrom by the presence of small amounts ofmonomeric units derived from silicon compounds of the formula I was verysurprising for the person skilled in the art, since this advance madepossible the utilization of a number of other advantages in combinedform, viz. a trouble-free dispersion preparation, the great stability ofthe synthetic resin copolymer dispersions to be used according to theinvention and their unexpectedly high pigment binding power. Only thecombination of these unexpectedly advantageous properties has made thepreparability of the dispersion paints, coating materials and syntheticresin dispersion plasters according to the invention free from solvents,film-consolidating auxiliaries and plasticizers at all possible. To thiscan be added that in the preparation of the synthetic resin copolymerdispersion the use of ammonium salts and amine salts such as, forexample, (NH₄)₂ S₂ O₈, may be generally dispensed with and the alkalimetal salts such as, for example, sodium persulfate, used in theirplace, in order that no unpleasant ammonia and/or amine odor may beproduced in the alkaline coating materials and construction protectivematerials for the user and the environment. Likewise amines such as, forexample, diethylamine and triethylamine as well as diethanolamine andtriethanolamine, as constituents of the aqueous preparations ofconstruction protective materials are avoided. For the same reasonparticularly the sodium salts of anionic dispersants are used as pigmentdispersants. The same holds for the emulsifiers in the polymerization.The sodium salts of, for example, sulfated oxethylated alcohols andalkylphenols are used and not the ammonium and/or alkylammonium salts.

In the production of the synthetic resin copolymer dispersions andparticularly in their demonomerization as well as in the production ofcoating materials and plasters, foam formation may be very annoying.This may be prevented by the use of small amounts, preferably 0.001-0.5%by weight, based on the dispersion, of antifoams based on natural fatsand oils, such as, for example, sperm oil and train oils, paraffin oil,long-chain alcohols such as cetyl alcohol, high-polymeric glycols andmixtures of these alcohols with fats as well as fatty acid polyglycolesters, sorbitol monolaurate and silicones.

It is true that the use of dispersion paints and plasters is at its mostadvantageous when employed immediately after being prepared. It is knownfrom experience, however, that the finished containers are often storedfor more or less prolonged periods at the manufacturer, at the dealerand/or at the user before being actually put into use. In order to avoidimpairment of quality, the construction protective materials are in mostcases treated by preservatives by the manufacturer. To protect theproducts against subsequent attack by fungi or bacteria, no or only verysmall amounts of biocidal additives are employed if possible.Alternatively, preservation can be achieved by heating the finishedproduct for 15 to 120 minutes at temperatures from 60° to 120° C., forexample by pasteurization or tyndallization (also called fractionalsterilization), also by cooling as well as by excluding air duringstorage in gas-tight containers under inert gas. Ultrasound, UVirradition and high-frequency fields may also be used for preservation.Furthermore, additions of minimal amounts of antibiotics, such as, forexample terramycin, streptomycin and subtilin are suitable, likewisequinosol (equimolar compound of o-oxyquinoline sulfate and potassiumsulfate).

Furthermore, the following, used in minimal amounts, can be inter aliaeffective preservatives: chloroacetamide, sodium benzoate, methyl, ethyland propyl p-hydroxybenzoates and sodium compounds thereof, sodiumsorbate, sodium formate, sodium borate as well as borax, hydrogenperoxide, lactic acid, formic acid, propionic acid, nitrites andnitrates, salicylic acid, dehydracetic acid, thymol(methylisopropylphenol), barium metaborate, dithiocarbamates,chloromethylisothiazolinone and benzisothiazolinone.

The invention is elucidated in greater detail by the examples below.

COMPARISON EXAMPLE 1

Preparation of a vinyl acetate/ethylene copolymer dispersion not useableaccording to the invention with subsequent residual monomer elimination

An aqueous solution, consisting of the following constituents, is placedin a pressure apparatus provided with a stirrer, Jacketed heating andmetering pumps: 10,700 g of water, 142 g of sodium acetate trihydrate,1760 g of a 20% by weight aqueous solution of nonylphenol oxethylatedwith 30 mol of ethylene oxide, 13,700 g of a 5% by weight aqueoussolution of hydroxyethylcellulose (HEC solution) (viscosity of the 2% byweight aqueous solution being 300 mPa.s), 572 g of a 30% by weightaqueous solution of sodium vinylsulfonate and 34.3 g of a 1% by weightaqueous solution of ferrous sulfate heptahydrate. The pH of the solutionis 11.2. The apparatus is freed from atmospheric oxygen and ethylene isintroduced in the apparatus under pressure. At an ethylene pressure of20 bar 5900 g of vinyl acetate and 10% of a solution of a reducing agentconsisting of 27.1 g of rongalite in 2 liters of water are metered in.The internal temperature is brought to 60° C. and the ethylene pressurehas increased to 40 bar. 10% of an initiator solution consisting of 27.1g of tert-butylhydroperoxide in 2000 g of water are then metered in atan internal temperature of 60° C. and the apparatus is cooled to conductaway the heat of reaction. 24,600 g of vinyl acetate, the remaining 90%of the solution of reducing agent and the remaining 90% of the initiatorsolution are subsequently metered in, the ethylene pressure beingmaintained at 40 bar. A solution consisting of 34.32 g of sodiumpersulfate in 800 g of water is then metered in and the internaltemperature is increased to 80° C. and maintained at this temperaturefor 1 hour. The greater part of the unreacted ethylene is subsequentlyremoved by gas with stirring and collected in a gasometer, and 2 litersof water are added. Vacuum is then applied and 2.6 liters of water arethen distilled off in the course of 2 hours, the residual content ofvinyl acetate of the dispersion being thus reduced to 0.05% by weightbased on the dispersion. By repeating the separation procedure aresidual content of vinyl acetate of 0.012% by weight is achieved.

Characterization of the resultant copolymer dispersion

    ______________________________________                                        Solids content (% by weight)                                                                             55                                                 pH (electrode measurement) 4.8                                                Viscosity (Pa.s)           0.5                                                Minimum film-forming temperature (MFT), °C.                                                       <0                                                 Freezing temperature of the polymer (Tg), °C.                                                     2                                                  ______________________________________                                    

EXAMPLES 1 TO 4

Preparation of vinyl acetate/ethylene/vinyltrimethoxysilane copolymerdispersions useable according to the invention with subsequentelimination of the residual monomers and other readily volatileconstituents

Polymerization is carried out in the apparatus and by the method ofComparison example 1 except that increasing amounts ofvinyltrimethoxysilane are dissolved in the total amount of 30,500 g ofvinyl acetate and the homogeneous vinyl acetate solutions resulting ineach case are used in the polymerization of the Examples 1 to 4. Thefollowing individual amounts of vinyltrimethoxysilane are added to thevinyl acetate:

    ______________________________________                                        In Comparison example 1:                                                                      0 g = 0% by weight, based on                                                 the copolymer                                                  In Example 1:   34.32 g = 0.1% by weight, based on                                           the copolymer                                                  In Example 2:   68.64 g = 0.2% by weight, based on                                           the copolymer                                                  In Example 3:  171.6 g = 0.5% by weight, based on                                            the copolymer                                                  In Example 4:  343.2 g = 1.0% by weight, based on                                            the copolymer                                                  ______________________________________                                    

The parameters of the resultant copolymer dispersions as well as thesolids content, the pH and the viscosity of the dispersions showpractically no change in Examples 1 to 4 from those in Comparisonexample 1. Only in Example 4 does the solids content of the resultantdispersion drop to 52.7% by weight and the mean particle diameterincreases to 0.9 μm. The essential characteristics of the resultantdispersion copolymers with increasing amount of the silane used are thedecreasing melt index, the reduction or absence of the so-called crazingof the coating and the improvement of the wet abrasion resistance of thecoating based on a high-fill indoor paint. The result of the comparisontests performed in order to obtain the characteristic parameters isgiven in a summary form in Table 1.

General formulation for high-fill dispersion indoor paints produced forcomparison tests

    ______________________________________                                                             Parts by weight                                          ______________________________________                                        Water                  3110                                                   Methylhydroxyethylcellulose                                                                          60                                                     (2% aqueous solution, visc. 3000 mPa.s)                                       Na salt of a polyacrylic acid of a MW 2000                                                           35                                                     (30% by weight aqueous solution)                                              Sodium polyphosphate   150                                                    (10% by weight aqueous solution)                                              Sodium hydroxide (10% by weight solution)                                                            20                                                     Preservative           15                                                     Antifoam               20                                                     Talc                   600                                                    Kaolin                 400                                                    Titanium dioxide       700                                                    Calcium carbonate (particle size: 90% by                                                             2300                                                   weight <2 μm)                                                              Calcium carbonate (particle size: 50% by                                                             1500                                                   weight <2 μm)                                                              Synthetic resin dispersion (55% by weight)                                                           1090                                                   Total amount of dispersion paint                                                                     10,000                                                 ______________________________________                                    

Preparation of dispersion indoor paints according to the precedinggeneral formulation

The methylhydroxyethylcellulose in powder form is sprinkled in the waterand dissolved with stirring; the solutions of the sodium polyacrylateand sodium polyphosphate and the 10% by weight solution of sodiumhydroxide are then added with stirring. The resultant viscous solutionis then treated with the preservative and the antifoam. Talc and kaolinare first dispersed in the mixture by stirring using a dissolver at astirring rate of 2000 rpm, the rate of stirring is then increased to5000 rpm and titanium dioxide and the varieties of calcium carbonate areadded. Dispersion is continued for a further 20 minutes at 5000 rpm, thetemperature of the pigment/filler paste increasing to 60° C. The mixtureis allowed to cool to 30° C., the pH being 9.3.

In order to examine the parameters of the synthetic resin copolymerdispersions described, in each case 891 g of the pigment/filler pasteare added with stirring to 109 g of the 55% by weight synthetic resincopolymer dispersion to be tested in each case (3 minutes using a Lenardstirrer at 1500 rpm). After one day the dispersion paints prepared inthis manner are spread onto a Leneta film using a 300 μm doctor bladeand after being dried for 5 days at 23° C. and 50% relative humidity,the coatings are placed in a Gardner apparatus and the number of doublerubbings (DR) according to Gardner, withstood by the coating, aredetermined. In this context increasing DR numbers denote increasingquality of the coating. The results may be found in Table 1.

                                      TABLE 1                                     __________________________________________________________________________                            Number of   Repeat of the                                                     double      measurements                                                      rubbings    after heat                                                        (DR)        treatment of the                                 Content of       according   coating (4 hrs                            Copolymer                                                                            vinyltrimethoxy- to Gardner  at 60° C.)                         dispersion*)                                                                         silane in the                                                                          Melt index of                                                                         withstood   DR acc.                                                                            Crazing                              from   copolymer                                                                              the copolymer                                                                         by the                                                                              Crazing of                                                                          to   of the                               example No.                                                                          % by wt. (i.sub.21.6/120 ° C.)                                                          coating                                                                             the coating                                                                         Gardner                                                                            coating                              __________________________________________________________________________    1      0.1      11.1    348   medium                                                                              275  slight                               2      0.2      4.8     658   none  591  none                                 3      0.5      2.1     659   none  607  none                                 4      1        0.3     449   none  296  none                                 Comparison                                                                           0        18.4    217   extensive                                                                           145  exten-                               Example 1                                sive                                 __________________________________________________________________________     *) Copolymer dispersions demonomerized according to the invention having      residual vinyl acetate content of 0.05% by weight based on the copolymer,     are used with the synthetic resin copolymer dispersions of Examples 1 to      4. The solids content of the dispersion paints is determined according to     DIN 53189 and is 62.75% by weight in each case. The volatile constituents     of the dispersion paints, consisting almost exclusively of water,             correspondingly amount to 37.25% by weight. After a det ermination by gas     chromatography at a transition temperature of up to 250° C., the       volatile constituents of the dispersion paints according to the invention     contain besides water only 0.0017% by weight of volatile nonaqueous           substances.                                                              

As the results in Table 1 indicate, the pigment binding power of thelow-emission indoor paints increases with increasing amount ofvinyltrimethoxysilane, when the molecular weight of the copolymerincreases (decreasing melt index i₂₁.6 at 120° C. corresponds to anincreasing melt viscosity of the copolymer, 21.6 being the weight of thedie in kg), while the so-called crazing diminishes.

EXAMPLES 5 TO 8

Example 2 is repeated in the Examples 5 to 8 with the proviso that inthe preparation of the copolymer dispersion according to Example 2 themean particle size of the dispersion copolymer obtained from vinylacetate and ethylene while retaining a vinyltrimethoxysilane content of0.2% by weight, is varied by a modification of the emulsifier/protectivecolloid system known to the person skilled in the art. It can be seenfrom this that the pigment binding power of the dispersion increaseswith decreasing particle size. The MFT of the dispersions is in theneighborhood of <0° C. Comparison dispersion indoor paints are preparedaccording to the general formulation given in Examples 1 to 4 for thepreparation of high-fill dispersion indoor paints, using the dispersionsof Examples 5 to 8, and the double rubbing tests according to Gardnerare carried out on the coatings prepared therefrom. The result of thesetests as well as individual details of the compositions and propertiesof the copolymer dispersions of Examples 5 to 8 are given in Table 2.

COMPARISON EXAMPLE 2

A commercially available vinyl acetate/vinyl chloride/ethyleneterpolymer dispersion having an MFT of 12° C. is used as comparison forthe copolymer dispersions of Examples 5 to 8. In the same manner as inthe Examples according to the invention, the addition of solvents to thesynthetic resin dispersion or to the dispersion paint is dispensed with.When this commercially available dispersion is used in a comparisonseries of experiments in a comparative manner with dispersions of theExamples 5 to 8, worse results are obtained than those with thecopolymer dispersions according to the invention having low MFTs and lowcontents of silane comonomer units. The results are given in Table 2.

                                      TABLE 2                                     __________________________________________________________________________                       Test of the coating                                                           Number of double                                                  Variation of the mean                                                                     rubbings (DR) Repeat of the measurements                          particle diameter                                                                         according to  after heat treatment of the                         of the copolymer                                                                          Gardner  Crazing                                                                            coating (4 hrs at 60° C.)             Example                                                                              according to Example 2                                                                    withstood by                                                                           of the                                                                             DR acc. to                                                                          Crazing of the                         No.    μm       the coating                                                                            coating                                                                            Gardner                                                                             coating                                __________________________________________________________________________    5      0.359        570     none 531   none                                   6      0.264       1373     none 904   none                                   7      0.218       1266     none 946   none                                   8      0.176       1034     none 1210  none                                   Comparison                                                                           0.161        593     medium                                                                             573   medium                                 Example 2                                                                     __________________________________________________________________________

EXAMPLE 9

556.7 g of electrolyte-free water (D-water), 40 g of a 20% by weightaqueous solution of oxethylated nonylphenol (oxethylation degree 30), 8g of sodium lauryl sulfate, 13.3 g of a 30% by weight sodiumvinylsulfonate and 3.3 g of crystallized sodium acetate are initiallyintroduced into a 2 liter flask provided with a stirrer, internalthermometer and nitrogen inlet, and mixed with stirring. 10% of amonomer mixture consisting of 558.9 g of vinyl acetate, 239.5 g ofbutylacrylate and 1.6 g of vinyltrimethoxysilane are added at roomtemperature and the mixture is heated. 1.6 g of sodium persulfate,dissolved in 19.2 g of water, are added at 35° to 45° C. and the mixtureis further heated at an internal temperature of 70° C. The remaining 90%of the monomer mixture is metered in in the course of 2.5 hours. 10minutes after the end of the monomer addition 0.8 g of sodium persulfatein 19.2 g of water are added and the dispersion is further heated for 2hours at 85° C. During this time the residual unreacted monomer isdistilled off using a distillation bridge, while a slow nitrogen streamis passed in, after which the content of residual monomers is 0.05% byweight, based on the dispersion copolymer. The dispersion is cooled andfiltered through a 160 μm sieve, 0.28 g of moist coagulate accruing asresidue. The dispersion has a solids content of copolymer of 55.1% byweight, a mean particle diameter of 137 nm and a film-formingtemperature (white spot/film tear) of <0°/2° C.

A dispersion paint is prepared from 891 g of pigment/filler paste and109 g of 55.1% by weight of the synthetic resin copolymer dispersionfrom Example 9, using the general formulation given in Examples 1 to 4for the preparation of high-fill dispersion indoor paints. A coatingprepared from this paint, dried for 5 days at 23° C., has a value of 500DR in the .Gardner abrasion resistance test without crazing.

COMPARISON EXAMPLE 3

The procedure of Example 9 is followed, except that a mixture of 560 gof vinyl acetate and 240 g of butylacrylate are used as the mixture ofmonomers. The resultant synthetic resin copolymer dispersion hasvirtually the same MFT as the copolymer dispersion prepared according toExample 9. Compared with the high-fill dispersion indoor paint preparedin Example 9, the synthetic copolymer dispersion not according to theinvention, obtained in the present case, yields a coating which, whendried for 5 days at 23° C., has a value of Only 300 DR in the Gardnerabrasion resistance test with a medium to strong crazing. This result isdistinctly worse than the result obtained in a comparative manner inExample 9 using the copolymer dispersion containing silanol unitsaccording to the invention.

We claim:
 1. A low emission dispersion paint, coating material andsynthetic resin dispersion plaster in the form of aqueous preparationsbased on aqueous synthetic resin dispersion polymers derived fromolefinically unsaturated monomers having a pigment volume concentration(PVC) of at least 60% and containing water, fillers, pigments, syntheticresin dispersion polymers and auxiliaries selected from the group ofwetting agents, disperants, emulsifiers, protective colloids,thickeners, antifoams, dyes and preservatives, wherein the non-volatilepart of the aqueous preparations contains35 to 94% by weight of afiller, 2 to 30% by weight of pigment, 0.1 to 10% by weight of anauxiliary and 4 to 35% by weight of synthetic resin dispersioncopolymer,based on the total non-volatile part, the aqueous dispersion of whichcopolymer possesses a minimum film-forming temperature (MFT) of <10° C.,and the synthetic dispersion copolymer has a content of 0.05 to 0.4% byweight of monomeric units derived from unsaturated hydrolyzable organicsilicon compounds of the formula ##STR3## in which R denotes an organicradical olefinically unsaturated in the .sup.ω -position and R¹, R² andR³ which may be identical or different, denote halogen or the group -OZ,Z denoting primary or secondary alkyl radicals or acyl radicalsoptionally substituted by alkoxy groups, or hydrogen, the content ofvolatile non-aqueous constituents of the aqueous preparations being 0.1%by weight, based on the total non-volatile part, and the pH of theaqueous preparation being in the range from 5.5 to 10 wherein after thecopolymer having been copolymerized, residual monomers being removed bydistillation.
 2. A paint as claimed in claim 1 wherein the syntheticresin dispersion copolymer contains monomeric units selected from thegroup consisting of vinyl esters, vinyl esters/ethylene, vinylesters/vinyl chloride/ethylene, vinyl esters/vinyl versatates, vinylesters/acrylic esters and acrylic esters/vinyl versatates/ethylene.
 3. Apaint as claimed in claim 1 wherein the synthetic resin dispersioncopolymer compounds are selected from the group consisting ofγ-acryloxy-propyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane,vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethylgycol-silane,vinyltriacetoxysilane, vinyltrichlorosilane, vinylmethyl-dichlorosilaneand γ-methacryloxypropyltris(2-methoxy-ethoxy) silane as hydrolyzablemonomeric units of the formula I.
 4. A paint as claimed in claim 1wherein the synthetic resin dispersion copolymer comprises mixtures ofdispersion copolymers, a part of which contains no monomeric units ofthe formula I and another part of which contains monomeric units offormula I in such an amount that the mean content of monomeric units offormula I in the total dispersion copolymer mixture is 0.05 to 2% byweight, based on the total synthetic resin dispersion copolymer mixture.5. A paint as claimed in claim 1 wherein the mean particle diameter ofthe synthetic resin dispersion copolymer particles is at least in theneighborhood of 0.1 μm or higher.
 6. A paint as claimed in claim 1wherein the aqueous preparations are free from residual monomers, fromlower alcohols and from ammonia and/or volatile amines or fromcomponents which give rise by cleavage to H₂ S or mercaptans, ifappropriate, and the total content of volatile non-aqueous constituentsof the aqueous preparations is <0.05% by weight, based on the totalnon-volatile part.
 7. A paint as claimed in claim 1 wherein thesynthetic resin dispersion copolymer contained in the aqueouspreparations and carrying silicon radicals from monomeric units of theformula I was prepared by radically initiated copolymerization of thefinely divided monomers having an amount of 0.05% to 2% by weight, basedon the total amount of monomer, of monomers of the formula I in aqueousmedium with the simultaneous use of hydroxyethylcellulose, nonionicemulsifiers and monomeric sodium vinylsulfonate as emulsifier/protectivecolloid system, and the volatile alcohol components which may haveformed by hydrolysis from the monomeric units of the formula I in theaqueous dispersion and any volatile amounts of residual monomers whichmay be present after the terminated polymerization reaction have beenremoved by distillation under reduced pressure.
 8. A paint of claim 1wherein the synthetic resin dispersion copolymer has a content of 0.1 to0.4% by weight of monomeric units derived from unsaturated hydrolyzableorganic silicon compounds of formula I.
 9. A low emission dispersionpaint, coating material and synthetic resin dispersion plaster in theform of aqueous preparations based on aqueous synthetic resin dispersionpolymers derived from olefinically unsaturated monomers having a pigmentvolume concentration (PVC) of at least 60% and containing water,fillers, pigments, synthetic resin dispersion polymers and auxiliariesselected from the group of wetting agents, disperants, emulsifiers,protective colloids, thickeners, antifoams, dyes and preservatives,wherein the non-volatile part of the aqueous preparations contains35 to94% by weight of a filler, 2 to 30% by weight of pigment, 0.1 to 10% byweight of an auxiliary and 4 to 35% by weight of synthetic resindispersioncopolymer, based on the total non-volatile part, the aqueousdispersion of which copolymer possesses a minimum film-formingtemperature (MFT) of <10° C., and the synthetic dispersion copolymer hasa content of 0.05 to 0.4% by weight of monomeric units derived fromunsaturated hydrolyzable organic silicon compounds of the formula##STR4## in which R denotes an organic radical olefinically unsaturatedin the .sup.ω -position and R¹, R² and R3 are individually -OZ, Z beingprimary or secondary alkyl, the content of volatile non-aqueousconstituents of the aqueous preparations being <0.1% by weight, based onthe total non-volatile part, and the pH of the aqueous preparationsbeing in the range from 5.5 to 10 wherein after the copolymer havingbeen copolymerized, volatile alcohol components formed by hydrolysisfrom the monomeric units of formula I and volatile amounts of residualmonomers being removed by distillation.